Twist-drill-grinding machine



N0. 607,306. Patented July [2, I898.

0. S. WALKER.

TWIST DRILL GRINDING MACHINE.

(Application filed Sept. 13, 1897.)

(No Model.)

Ir varflnr @a/AZ7 @QM/ as ca, moTa-utua. wAsum NirEo STATES TATENT rrrcn.

TWlST-DRlLL-GRINDING MACHINE.

SPECIFICATION forming part of Letters Patent No. 607,306, dated July 12, 1898.

Application filed September 13, 1897. Serial No. 651,657. (No model.)

To all whom it may concern.-

Be it known that I, OAKLEY S. WALKER, a citizen of the United States, residing at \Vorcester, in the county of IVorcester and State of Massachusetts, have invented certain new and useful Improvements in Twist-Drill- Grinding Machines, of which the following is a specification.

Among the objects of my present invention may be mentioned improved devices for holding, adjusting, and grinding twist drills, straight-fluted drills, and flat drills, such as arecommonly usedformetal-drilling. These drills, previously ground almost entirely by hand, are now by the advancement of the art usually held in a pivoted chuck with the end of the drill adjusted in a certain definite position from the chuck-pivot eccentric to the.

October 1, 1880, and No.l25,839, of April 15,

1890, I have shown and described devices for accomplishing these ends. My present invention has to do with similar devices of a simplified and improved nature; and to this end my invention consists of the new and novel features described hereinafter.

Referring to the accompanying drawings, like figures and letters of reference indicating like parts, Figure 1 is a side elevation, partly in section, of my improved drill-grinding machine with a drill in place in the holder. Fig. 2 is a front end elevation with a part of the drill-adjusting mechanism in section and the swinging part of the drill-holder removed. Fig. 3 is a plan view of the swinging part of the drill-holder, illustrating the method of setting same for a drill. Fig. 4 is a diagram illustrating the method of setting the drillholder for the various-sized drills. Fig. 5 is a rear end View, partly in section, of the swinging part of the drill-holder; and Figs. 6, 7, 8, 9, 10, and 11 are detail views of same, illustrating the operations of the drill-lip rest. Fig. 2 is a part vertical section through the drill-holder, showing the feeding mechanism and the pivot-bearings. Fig. 13 is a rear end view of the drill-holder and the pivoted drillholder support, partly in section.

A is the main supporting-stand of the machine, provided with a projecting bracket A for the reception of a slide and the drill-holding mechanism.

B is the grinding-spindle, running in bearings A of the stand A.

The spindle B is driven by a belt on the pulley O, fastened to the spindle by the setscrew 0 One end of the spindle B is provided with a chuck B, recessed for the reception of the back edge of the emery-wheel D and closely fitting the same, thus providing a safety-guard to prevent the bursting of the wheel. The spindle B is also provided with an externally-threaded projecting end B upon which is mounted the nut 13 for holding the wheel D in place longitudinally.

Upon the projecting bracket A is mounted the inclined slide E, operated transversely by the screw and crank E.

At the right-hand end of the inclined slide E is a slotted vertical projection E, also inclined, upon which is adj ustably mdunted the longitudinal slide H, which is provided at one side with the pivot 11 for the swinging drill-holder. This slide II is held against the slotted vertical projection E by means of the nut G and the stud G threaded into II and passing through the aforesaid slot,clainping the slide II in place at will. Upon the stud G and between the nut G and the clamping-surface is loosely mounted the pinion G, provided at one side with an operating-handle G. Upon the transverse slide E is mounted a stationary rack F, in mesh with the pinion G.

The weight of the longitudinal slide II and its parts is supported by a horizontal project ing surface E of the slide E. (See Fig. 2.) To prevent a lifting tendency of the slide H while being adjusted, a roller G is provided, rolling easily upon the stud G between the walls of the .slot E in the part E aforesaid and bearing only upon the top surface of said slot. (See Fig. 2.)

It will be noticed that the direction of movement of the longitudinal slide II is inclined from a horizontal plane. The object of this inclination will be explained hereinafter. To prevent the slipping back of the slide H on the said incline when the nut Gr is loosened, a coil-spriu g G is provided which is recessed into one side of the pinion G and bears against the nut G It is made with sufficient tension to create the necessary friction to hold the parts in place when the nut G2 is slackened.

Upon the pivot II is mounted the drillholder support K, pivoted on pointed bearings at the top and bottom and having adj ustment for Wear by means of the pointed screw-threaded bearing K at the bottom. The top surface of the support K is provided with V-shaped ways or tracks K, fitting corresponding grooves in the bottom of the sliding drill-holder I. A great advantage attained by this construction is the prevention of slack motion due to wear when in use, which would cause inaccuracies in the clearance of drills ground. The lower portion of the support K is in the form of a hollow cylinder with part of one side cut away for the reception of the pivot II.

The top of the drill-holder support K is provided between the tracks K aforesaid with a slot for the reception of a bolt 1 which passes through a hole in the drill-holder I and is provided with a nut I for clamping the drill-holder I to the support K in any desired position at will. The support K is also provided upon its top surface with a projecting pin K beyond the surface covered by the drill-holder I. The object of this pin will be explained farther on.

The drill-holder I is provided with a c011- tinuous V-shaped trough its entire length to retain the various-sized drills. A portion of this trough is provided with a longitudinal slot 1, extending completely through the drill-holder vertically. This slot is for the reception of a bindingscrew L which enters from the under side and is threaded into the sliding tail-stock L. By this means the said tail-stock can be moved along and clamped in any desired position.. The tail-stock L is fitted to conform to the shape of the V-trough at its base, and it is evident that when it is clamped in place all lost motion will be taken up, also that its tendency will be to spread the trough apart in some degree, which would be objectionable. To overcome this fault, I groove the under side of the drill-holder upon each side of and parallel to the slot I. A sliding shoe L is provided with raised tracks to fit the aforesaid grooves. This shoe forms a bridge across the slot I and a washer for the binding-screw L and prevents the spreading of the holder when the said screw is tightened. By this arrangement the advantages of a slotted V-shaped trough for a tail-stock or stop is obtained which would otherwise be impracticable.

L is the feed-plunger, provided at one end with a flanged portion fitting the V-trough and forming a stop for the drill, the other end sliding in a hole in the tail-stock L and being fed out by the feed-screw L which has a tapered point fitting a like-tapered recess in the end of the feed-plunger. The object of this construction is to provide an easy means of creating a friction to hold feedscrew L more securely in place.

At the left of the V-shaped trough and near the upper end the drill-holder is supported on the V-shaped ways on top of the support K, as previously described. The movement of the drill-holder upon these ways, which. are inclined horizontally to the axis of the drill, determines the varying clearance of different-sized drills, the principle of which has been applied to many other drill-grinding machines and is fully explained in my Patent No'. 411,85, dated October 1, 1889, Sheet 3, Fig. 6, of specification, line No. 95.

The end of the drill-holder over the V- shaped ways K above mentioned is beveled off at an angle both to the said ways and to the axis of the drill. This end of the drillholderand the pin K have an important bearin g on the setting of the drill-holder for varying sizes of drills. The drill to be' ground is first inserted between the pin K and the end of the drill-holder and determines the longitudinal adjustment of the holder upon the V-shapcd ways K, before mentioned.

Referring to the diagram Fig. 4, the pin K is represented by a point. e (Z is the line of adjustment for the drill-holder longitudinally on the V-ways, and c f the line representing the end of the drill-holder or line of drill contact. The line a b, drawn through the pin K is perpendicular to the end of the drill-holder or line cf. It is evident that the shortest distance from the pin K to the line 9 f will be measured upon the line a Z). Hence the centers of all drills inserted between K and cf willlie somewhere in the linea Z). The distance K to 1 equals one inch, 1' to 2 equals two inches, and K to 3 equals three inches. These distances will represent diameters of drills of corresponding sizes. Assume diagram to represent the setting of the drillholder for drills one inch in diameter. The point of drill contact on line cf will evidently be at 1. From the points 2 and 3 draw lines parallel to 0 (Z, (the line of ad j ustmen t,) meeting efin points 4 and 5. It is evident that in setting the holder for a two-inch drill the point 4- will coincide with the point 2, and hence point 4: will be the point of drill contact for a two-inch drill and, similarly, point 5 will be carried to point 3 and come in contact with a three-inch drill. Thus it is evident that no two drills of different diameter can have the same point of contact upon the end of the drill-hold er. The wear is thus distributed, and a variable setting can be provided for by forming the drill-holder end to a curve. In my Patent No. 425,839, of April 15, 1890, I have shown and described a pair of projecting angular caliper-jaws made parallel. The difficulty encountered is in the binding of the drills between these jaws, making them difficult of removal after the holder is clamped. In my present device, the pin K having but a single line of contact for all sizes of drills, the least lateral motion of the drills will free the same, and little care is necessary in machining the surfaces.

The end of the drill-holder I which abuts on the emery-wheel is provided with a shallow horizontal groove for the reception of the adjustable drill-lip rest J, held in place by the screw J, threaded into same, and which passes through a slot 1 in the end of the drillholder, binding the lip-rest firmly against the same when desired. This rest is adjustably fitted in the groove aforesaid and can be horizontally adjusted without changing its angularity. Thus if the rest should become worn it can simply be moved along and clamped in a new position or to bring the line of drill contact in the original position. Further- 1nore,I make thelip-rest reversible and doubleended, so that different-shaped ends can be employed at will. In Fig. 6 is shown a squareended lip-rest set for an ordinary two-lipped twist-drill. In Fig. 8 is shown the same liprest adjusted to throw the drill out of center of the V-trough. By this means I am enabled to obtain an increased clearance upon any drill at pleasure, as the same is thus set with greater eccentricity to the holder-pivot. Fig. 9 shows the operation of the squareended lip-rest to the setting of a flat drill, and Fig. 10 the same for a four-lipped drill. Fig. 11 shows the liprest reversed and a pointed end employed for a multiple-toothed drill or reamer.

The operation of my improved twist-drill grinder is as follows: The nut G2 is loosened, and by means of the handle G of the pinion G the drill-holder I and support K are drawn back with the slide II some distance away from the emery-wheel and temporarily Y with the cutting end projecting past the liprest J a slight distance and the edge of the drill-groove in contact with the said rest. The tail-stock is now moved up and clamped with the sliding plunger L in contact with the shank of the drill. With the right hand holding the drill and holder loosen the nut G and with the handle G move the drill and holder up into light contact with the grinding-wheel and tighten nut G While the right hand holds the drill in place, with the left hand 011 the feed-screw L swing the holder and drill past the face of the grinding-wheel D, at the same time feeding the drill to the wheel the desired amount for sharpening same by means of the screw L aforesaid, reversing the lips of the drilfrequently to grind same of equal length. To carry the work to a different partof the surface of the grinding-wheel, the transverse slide E is moved by the crank-handle E,Which actuates a feed-screw in any usual and convenient manner to move the same. Should it now be desired to grind a larger drill than the one previously ground, the same operation is gone through with as above described, and it will be found that the pivot ll is farther away from the drill-point and the grinding-wheel than in the previous case when the drill is set ready to grind. This is obvious from the foregoing description. It follows then that as the adjustment away from the emery-wheel is inclined downward the slide II and pivot 11, carrying the drill and holder, are also lower than in the previous position. The object aimed at by this construction is to maintain all drill-points in approximately the same horizontal plane. The inclination of the line of longitudinal adjustment of the slide II will compensate for the unavoidable elevation of drills in the V-grooved trough as the diameters increase.

In all previous drill-grinding machines of this nature no provision has been made to remedy this difficulty, and large-sized drills are carried nearly out of range of the grinding-wheel.

Having now described myinvention, what I claim as new, and desire to secure byLetters Patent in the United States, is as follows:

1. In a drill-grinding machine the combination of a continuous \l-.shaped trough for hold in g the drills, a longitudinally-ad j ustable tail-stock fitting the said trough for feeding the drills to a grinding-wheel, and an adj ustable drill-lip rest forsetting the drillin proper position, the direction of the lip-rest adj ustment being across the V-shapedtrough to provide for a variation of the clearance of the drill-lips substantially as shown and clescribed.

2. In a drill-grinding machine, the combination of a slotted V- shaped trough for holding the drills, the said trough being provided with parallel grooves longitudinally, a tailstock adjustably mounted in the said trough and clamped by a screw through said slot and a bridge-piece or washer spanning said slot and provided with lugs or ways fitting said grooves, said bridge-piece being perforated for the tail-stock binding-screw and preventing the spreading of the trough when said binding-screw is tightened, all substantially as set forth.

3. In a drill-grinding machine the combination of a continuous V-shaped trough for holding the drills and the feeding tail-stock, a reversible drill-lip rest and a pivoted drillholder support provided with V- Shaped ways at the top upon which the drill-holder trough is adapted to be adjusted as and for the purpose described.

4. In a drill grinding machine the combination of an adjustable drill-lip rest, a V- grooved drill-holder with beveled end and a pivoted drill-holder support provided with a stop or pin from which, measuring from the said beveled end of drill-holder the setting of the drill-holder is determined for the different-sized drills substantially as shown and described.

5. In a drilLgrinding machine the combination with the drill-holder and clrill-h01der support of apivot and longitudinal feed-s1ide whose line of adjustment away from the grindin g-wheel is inclined downward from a horizontal plane for the purpose above set forth.

6. In a (lrilLgrinding machine the combination of a V- grooved drill-holder, a pivoted drill-holder support,- and a longitudinallyadjustable pivot-slide, adjustable obliquely from a vertical plane substantially as shown and described.

OAKLEY S. WALKER.

\Vitnesses:

EDNA I. TYLER, C. W. W001). 

